Drill bit



Aug. 23, 1932. i e. H. GILMAN v 1,873,757

' DRILL BIT 0 Filed Nov. 26, 1950 GEORGE H.GILMHN- VENT OR &

ATTORNEY Patented Aug. 23, 1932 UNITED STATES PATENT OFFICE GEORGE E. GILMAN, OF BELMONT, MASSACHUSETTS, ASSIGNOR TO WORTHINGTON PUMP AND MACHINERY CORPORATION, OF NEW YORK, 'Y., A CORPORATION OF VIRGINIA DRILL Brr Application filed November 26, 1930. Serial No. 498,249.

This invention relates to drills and particularly, but not exclusively to those for drilling rock, coal and like formations. An object of the invention is to provide a drill bit which is comparitively simple in the formation of its cutting edges, one which may be readily and accurately resharpened, and one which has its cutting edges so arranged that they will act upon the substance being drilled in such manner as to insure fast and true cutting, with the cuttings broken up into such sizes as to be readiiyldislodged and removed from the drill With these and other objects in view, as may appear from the accompanying specificatlon, the invention consists of various features of construction and combination of parts, which will be first described in connection with the accompanying drawing, showing a drill bit of the preferred form embodying the invention, and the features forming the invention will be specifically pointedout in the claim.

In the drawing:

Fi 1 is an edge elevation of the improved drill it.

Fig. 2 is a sideelevation of the drill bit.

Fig. 3 is an end view of the bit and Fig. 4 is a diagrammatic view illustrating the manner in which the bit acts upon t e formation being drilled.

Referring more particularly to the draw: ing, the improved drill bit is shown as formed upon the end of a drill bar 1, but it is to be understood that the cutting edge arrangement of the bit may be employed on detachable drill bits such as disclosed in my companion application #498,250 filed of even date herewith, without departing from the spirit of this invention.

The bit 2 has two parallel cutting edges 3 and 4 formed thereon and extending transversally to the longitudinal axis of the bit 2. These cutting edges 3 and 4 are spaced equidistant from a line intersecting the longitudinal axis of the drill bit perpendicularly thereto as clearly shown in Figs. 1 and 3-of the drawing. The bit inclines inwardly away from the cutting edges 5 and 6 to the medial long line between them, as shown at 5 and 6 and it also inclines inwardly or rearwardly and outwardly from the cutting edges 3 and 4 -a distance equal to the inner inwardly inclined faces 5 and 6 thereby providing four angled faces 5, 6, 7 and 8 which are of substantially the same size.

A pair of right angled extending cutting edges 9 and 10 are provided on the drill bit and they extend at right angles to the cutting edges 3 and 4 at the transverse centers of these cutting edges. The relatively short rightangled cutting edges in 9 and 10 align one with the other and are also in ali ment with but extend at right angles to t e axis of the drill bit. I

The bit is shown as provided with the usual type of axial opening 11 which permits the passage of fluid into the drill hole for blowing or washing out the cuttings. However, it is to be understood that this opening may open at one side of the bit if desired without departing from the spirit of the present invention.

Fig. 4 of the drawing illustrates diagrammatically the action of the various cutting edges 3, 4, 9 and 10 on the formation or material being drilled and by particular reference to this figure it will be seen that the parallel relatively long cutting edges 3 and 4 cut the material being drilled into relatively narrow triangular cuttings or sections as indicated at A while the short right angular cutting edges 9 and 10 break up these elongated triangular sections A into minute triangular and rectangular sections as shown at B. The right angular cutting edges 9 and 10 cut across the cuttings of the parallel cutting edges 3 and 4 as clearly shown by the dotted lines 0 in Fig. 4 of the drawing.

From the foregoing description taken in connection with the accompanying drawing it will be apparent that a drill bit for drilling rock, coal and like formations has been provided which is comparatively simple in construction, embodying a minimum number of cutting edges to provide a maximum breaking up or cutting of the material being drilled and also that the bitissturdy and strong in its construction eliminating any relatively thin or weakened portions leading to cutting edges.

It will be understood that the invention is not to be limited to the specific construction or arrangement of parts shown but that they may be widely modified within the invention defined by the claim.

What is claimed is: a

As a new article of manufacture, a drill bit 10 comprising a air of parallel cutting edges disposed equi-distant from the axis of the bit and extending the full width of the bit, and a pair of radial cutting edges equi-distant from the ends of the parallel cutting 15 edges, said radial cutting edges extending inwardly to the cutting edge of the adjacent of said parallel cutting edges and projecting outwardly from the axis of the bit to a distance from the axis substantially equal to the a distance of the ends of the parallel cutting ed es from the axis.

n testimony whereof I afiix m signature.

GEORGE H. ILMAN. 

